Gramme armature dynamoelectric machine



1967 J. HENRY-BAUDOT 3,354,333

GRAMME ARMATURE DYNAMOELECTRIC MACHINE Fiied July 27, 1964 N 17 1a 2s 9 2 2 20 '19 4 6 FIG 3 F|G.4 FIGS F166 United States Patent Ofitice 3,354,333 GRAMME ARMATURE DYNAMOELECTRIC MACHINE Jacques Henry-Baudot, Antony, France, assiguor to Printed Motors Inc., New York, N.Y.

Filed July 27, 1964, Ser. No. 385,221 Claims priority, application France, Aug. 21, 1963, 945,327, Patent 1,373,824 11 Claims. (Cl. 310-268) The present invention concerns improvements in or relating to dynamoelectric machines, for example, of the disc type with a Gramme armature, that is to say a toroid carrying an uniformly wound winding, said winding being electrically connected in a closed loop and the current thereof being conducted thereto by means of brushes, said armature being concentrically arranged with respect to a ring of field creating magnetic poles.

The purpose of the invention is to improve the structures of such machines, and chiefly, the structures of such Gramme armatures.

In a conventional Gramme armature, an insulated wire is spirally wound on a toroidal carrier and this wire can only be of a constant cross-section; consequently, if one makes the turns of the spiral contact each other on the outer portion of the carrier, such turns will overlap in the inner portion, or conversely, if one winds the turns so as to be in contact with each other on the inner side of the carrier, the turns will be spaced apart on the outer side thereof. In both cases, the toroidal surface is ineffectively used and the electromagnetic efficiency cannot be an optimum. Further a separate commutator must be provided in the machine and consequently the efiiciency thereof is further decreased.

According to a feature of the invention, a Gramme armature comprises the combination of a toroidal core and a ring integral with said core and extending in a median plane thereof perpendicular to the axis of the core, such a core and ring member including a magnetic material at least in the core part thereof and having an insulating surface. Lamel-lar conductor means are intimately adhered to said insulating surface and defined around the core, a continuous and closed spiral covering nearly the entire surface and defining further on said ring a commutator of as many sections as are turns in said closed spiral.

According to another feature of the invention, such lamellar conductor means are printed-circuit conductor means, obtained from any of the so-called printed-circuit techniques, i.e. any technique capable of repeatedly reproducing a conductive pattern on a surface and firmly adhering thereto.

According to another feature of the invention, said ring extends towards the inner side of the core and also acts as a carrier means for mounting the armature on a shaft.

A machine according to the invention comprises such a Gramme armature associated with magnets placed on either side of the core and a pair of brushes bearing on the commutator sections.

These and further features will be described in detail with reference to the accompanying drawings, wherein:

FIG. 1 is a partial elevation view, in cross-section and FIG. 2 is a partial top view, of a first example of embodiment of a machine according to the invention;

FIG. 3 is a section on the lines 3-3 of FIG. 1;

FIG. 4 is a section on the lines 4-4 of FIG. 1; and

FIGS. 5 and 6 are views similar to those of FIGS. 3 and 4, defining an alternative embodiment of the armature of said machine.

In said example of embodiment, the toroidal core 1 is made of square cross section, this being of course a 3,354,333 Patented Nov. 21, 1967 matter of choice and not imperative. Said magnetic core 1 is sheathed by two half-shells 2 and 3 of insulating material and said half-shells have edges integral therewith, inner edges 4' and 5, outer edges 9 and 10. Said edges define two insulating rings, an inner one and an outer one. The inner ring extends on a sufficient breadth to enable an easy and plain attachment of the armature to a shaft 8 by means for instance of annular plates 6 and 7 pressing on opposite sides of said edge ring and afiixed to the shaft. The outer ring is of limited radial extent since it is only provided here for through-connection purposes which will be herein later explained. Instead of providing two halfshells it would have been possible as well to sheath the magnetic core 1 with a moulded thermosettable or thermopolymerisable resin defining both the sheath on the core proper and the inner and outer rings, or in other words, with the inner ring, since in such a case, the outer ring is no longer imperative. Such an alternative is too obvious to need any further showing or discussion.

The field induction magnets are shown at 25 and 28 on FIG. 2, each of them may be in two parts as shown at 24 and 25 in the cross-section view of FIG. 1 for ease in mounting them around the core and taking the outer radial edge in due consideration. Of course, when said outer edge is omitted, the division of the magnets in two parts may be also omitted if desired.

When however one wishes to make the commutator external to the core, the outer ring may be extended and the inductor field magnets may be distributed in two rings facing each other from opposite sides of the armature. Such an alternative increases the overall diameter of the machine, without any necessity thereto, so that said alternative is only indicated as a possibility of embodiment.

The commutator comprises, in the example shown, conductor sections 13 on which bear, after the final mounting of the machine, brushes such as 23. These sections are parts of the conductive coatings of the member constituted by the magnetic core 1, its sheath 2-3 and the inner ring 45. They are end portions or extensions of half-turn conductors which are printed or otherwise formed adhering on the surfaces of the half-shells. The same applies to the short sections 18 on the other face of the inner insulating ring. Practically the blades are shown equal for symmetry reasons.

All conductors are substantially contiguous but have narrow gaps therebetween and, from one half-shell to the other one, they are so oriented that a continuous closed spiral is obtained. This forms a winding of the true Gramme armature type once the thru-connections as 21 and 22 are made for example, by hole metallization of holes provided at the near edge of the half-shells.

Consequently, the commutator and the winding are simultaneously obtained with a nearly total coverage of the insulating surfaces. In order to ease the commutation, the commutator sections 13 are slanted with respect to the radial direction. The winding proper is made from parts 1-2 and 14 of the condctive coating of the half-shell 3 and the parts 17 and 19 of the conductive coating of the half-shell 2, plus the link parts 11, half-shell 3, and 16, half-shell 2, between the active portions of the turns, and the connections 22 and 21. Connections 22 are made be tween the conductor coatings 1S and 29 of the half-shells on their outer edges.

In the example of FIGS. 1 to 4, the active portions 1247 and 1549 of the winding are shown orthogonal to the upper and lower faces of the core, and consequently the inactive portions 11 and 16 are slanted in opposite directions, for defining the pitch of the spiral. In the modification shown in FIGS. 5 and 6, the active portions are slanted for defining the pitch of a turn of the spiral and the inactive parts are substantially parallel to the axis of rotation. Of course, the progressive pitch may be obtained by the slants of both the active and inactive parts, which is now obvious from the two shown examples. When the core is not rectangular in cross-section, but has a cross-section of circular or ellipsoidal shape, the discrimination between active and inactive parts becomes indefinite and the pitch of the spiral may be better defined from a uniform slant on each one-half of the core, the upper and the lower ones for instance, or the external and internal ones, as the case may be. In any case, as said, the conductors are distributed over the quasi-totality of the surface of the core, from which the efiioiency of the armature is maximum.

The printing of the Winding and commutator may have recourse as said to any printed-circuit technique. Preferably, the half-shells have previously been Wafiled for defining thin relief lines such as 26 and 27 in the insulation material. Copper is thereafter deposited on the insulating material up to a thickness more than the depth of the depressions between the relief ridges, and thereafter the conductor ridges are abraded for the thus inlaid conductors of the winding and commuator sections. By varying the depth of the depressions at the locations of the inactive parts of the winding and of the collector blades in the direction of a greater depth for such parts, the conductor thickness is greater in such parts of the circuit and consequently the resistance is lower, which increases the electromagnetic efficiency of the armature. For other printed circuit techniques, a similar result may be obtained by an overdeposition of copper on a first one, electrolytically for instance after the first deposition is made.

Instead of providing a magnetic core sheathed by an insulating material, one may have recourse to a magnetic material which is also insulating so that the deposition of conductors thereon may be directly made on the surfaces of such an insulating and magnetic member moulded as a core plus at least one cornmuator ring, with thru-connections from one face to the other one of said member.

The inductor magnet ring may be further so shaped as to substantially enclose the core if required, the brushes being nearer the center of the inner ring which is partly covered by the magnets.

Any other variation from the above shown and described arrangements does not escape the field of the invention as defined by the appended claims.

What is claimed is:

1. A rotary disc-type dynamoelectric machine of the G ramme armature type comprising in combination:

a disc rotor member including a toroidal core and a flat annulus integral with and extending perpendicularly to the axis of rotation of said core, at least the core portion of said member being formed of magnetic material;

an insulating covering surrounding and adhered to said core;

a closed spiral winding comprising a series of conductive members intimately bonded to the exterior of said insulating covering, said winding including commutator sections overlying and intimately bonded to said flat annulus portion of said rotor member, there being the same number of commutator sections as there are turns in said winding, said winding and com mutator sections substantially covering said rotor member;

a magnetic field structure at least partially surrounding said rotor member;

and brushes contacting said commutator sections.

2. Machine according to claim 1, wherein the conductive Winding and commutator sections consist of printedcircuit conductors on the said insulating covering.

3. A machine as defined by claim 2 wherein said commutator sections and the active portions of said closed spiral winding are thicker in cross section than the inactive portions of said spiral winding.

4. Machine according to claim 1, wherein the core is made of a material which is both magnetic and conductive and said insulating surface obtained by an insulating sheathing of said core with extended portions for making at least one inner ring perpendicular to the axis of rotation of said core.

5. Machine according to claim 4, wherein said sheathing comprises two half-shells with edges in the mid plane of symmetry of the magnetic core.

6. Machine according to claim 1, wherein said core and said annulus are made from a magnetic insulating material.

'7. Machine according to claim 4, wherein at least on the inner side of the core, thru-connections are made for closing the turns of the spiral winding coating on said insulating surface.

8. Machine according to claim 6, wherein at least on the inner side of the core, thru-connections are made for closing the turns of the winding coating on the surface of said insulating member.

9. Machine according to claim 7, wherein said commutator sections extend from said conductor coatings, radially inwardly beyond the said thru-connection area.

10. Machine according to claim 1, wherein the conductive conductor coating of the commutator is constituted of commutator sections slanted with respect to the radii of said rotor.

11. Machine according to claim 5, wherein a short outer edge is provided in the insulating sheath for the external thru-connections between the conductors of the spiral winding. 7

References Cited UNITED STATES PATENTS 9/1948 Stahl 3l0267 

1. A ROTARY DISC-TYPE DYNAMOELECTRIC MACHINE OF THE GRAMME ARMATURE TYPE COMPRISING IN COMBINATION: A DISC ROTOR MEMBER INCLUDING A TOROIDAL CORE AND A FLAT ANNULUS INTEGRAL WITH AND EXTENDING PERPENDICULARLY TO THE AXIS OF ROTATION OF SAID CORE, AT LEAST THE CORE PORTION OF SAID MEMBER BEING FORMED OF MAGNETIC MATERIAL; AN INSULATING COVERING SURROUNDING AND ADHERED TO SAID CORE; A CLOSED SPIRAL WINDING COMPRISING A SERIES OF CONDUCTIVE MEMBERS INTIMATELY BONDED TO THE EXTERIOR OF SAID INSULATING COVERING, SAID WINDING INCLUDING COMMUTATOR SECTIONS OVERLYING AND INTIMATELY BOUNDED TO SAID 